feat(php-shim): give ported exceptions PHP's class hierarchy

Ported exceptions were flat structs reached with `downcast_ref`, so
Composer's `catch (\RuntimeException $e)` only matched the exact leaf
type and `get_class($e)` had nothing to report. Each exception now
embeds an instance of the class it extends and travels inside an
`AnyThrowable`; `Catch::catch`/`catch_mut` walk that chain, and
`PhpClass::php_class_name` yields the PHP FQCN.

Dropping the `std::error::Error` impls from the exception types leaves
`AnyThrowable` as the only route into an `anyhow::Error`, so the walk
cannot be bypassed. A `no_exception_downcast` linter catches the
`downcast::<X>()` calls that would now silently answer `None`.

Three sites change behavior as a result: the `TransportException`
exit-code override reaches `MaxFileSizeExceededException`, the
`catch (\LogicException)` in findSimilar() reaches its subclasses, and
rendered exception titles carry the real class name rather than a
guess. `get_class_err()` is no longer a `todo!()`, which re-enables
FilesystemRepositoryTest::testCorruptedRepositoryFile.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

1 files changed, 15 insertions, 23 deletions

diff --git a/crates/shirabe/src/repository/path_repository.rs b/crates/shirabe/src/repository/path_repository.rs
index ec2da043..313fc75e 100644
--- a/crates/shirabe/src/repository/path_repository.rs
+++ b/crates/shirabe/src/repository/path_repository.rs
@@ -56,11 +56,9 @@ impl PathRepository {
         process: Option<std::rc::Rc<std::cell::RefCell<ProcessExecutor>>>,
     ) -> anyhow::Result<Self> {
         if !repo_config.contains_key("url") {
-            return Err(RuntimeException {
-                message: "You must specify the `url` configuration for the path repository"
-                    .to_string(),
-                code: 0,
-            }
+            return Err(RuntimeException::new(
+                "You must specify the `url` configuration for the path repository".to_string(),
+            )
             .into());
         }
 
@@ -172,13 +170,10 @@ impl PathRepository {
                 }
             }
 
-            return Err(RuntimeException {
-                message: format!(
-                    "The `url` supplied for the path ({}) repository does not exist",
-                    self.url
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "The `url` supplied for the path ({}) repository does not exist",
+                self.url
+            ))
             .into());
         }
 
@@ -355,10 +350,10 @@ impl PathRepository {
 
             self.inner
                 .add_package(self.loader.load(package.clone(), None).map_err(|e| {
-                    RuntimeException {
-                        message: format!("Failed loading the package in {}", composer_file_path),
-                        code: 0,
-                    }
+                    RuntimeException::new(format!(
+                        "Failed loading the package in {}",
+                        composer_file_path
+                    ))
                 })?);
         }
 
@@ -371,13 +366,10 @@ impl PathRepository {
         if defined("GLOB_BRACE") {
             flags |= GLOB_BRACE;
         } else if self.url.contains('{') || self.url.contains('}') {
-            return Err(RuntimeException {
-                message: format!(
-                    "The operating system does not support GLOB_BRACE which is required for the url {}",
-                    self.url
-                ),
-                code: 0,
-            }
+            return Err(RuntimeException::new(format!(
+                "The operating system does not support GLOB_BRACE which is required for the url {}",
+                self.url
+            ))
             .into());
         }